You will get a more efficient motor on the Carrier for the furnace blower, I have the consumption sheets somewhere. It was apx 25% less on the Carrier VS DC blower. The Carrier thermostat that allows fan speed control at the stat is cheaper on Carrier by 1-200$. And I beleive has more features. Get the 10 yr warranty. The variable speed motors although redesigned do fail.
Get factory electric consumption sheets for both units for furnace and heat pump to make your own decision. Ive decided on carrier. Also because the secondary coil on the Lennox furnace looks to be impossible to clean easily, by its design. On an older 3 yr Lennox Dimension
Be sure you have a load calc done in writing, upping AC efficiency can often leave to much humidity if the unit is near to being oversized. If
3 is what you had and it was correct a new 3 ton has a higher seer, you may only want 2.5 ton . This was my mistake. Also if you plan future insulation or doors or windows figure this in now. Here again I made a mistake and insulated afterwards and my AC is oversized now. I must run
2 dehumidifiers to really remove humidity.
Also for the furnace, does yours keep up or is it underpowered, I down graded from 110000 btu to 47000 btu, now I get a more even comfortable heat, but I could have gone even lower. The Carrier is made to run more of the time at low fan speed. Here it is a matter of comfort and heat eveness.
In the end it is the installer that counts. Being sure he is real good, works with you and gets you the properly sized equipment. To small an AC , you wont cool, to large you will be humid and clammy. To small a furnace it will strugle, to large it will have heat swings, uneven heat and short cycle. Remember get a load calculation in writing, guessing is not going to work.